Non-linear photoluminescence from graphene

The authors performed a detailed spectroscopic investigation varying both excitation energies and intensities to test these models. Graphene photoluminescence is found to be very broad ranging from 600 to 1200 nm. While the authors observe different photoluminescence spectra at different excitation energies no pronounced power dependence is found. Raman spectroscopic imaging, providing information on substrate-induced doping, defects and strain, is correlated with the local non-linear PL characteristics.